The radiolarian assemblages of the Bonarelli Horizon in the Umbria-Marche Apennines and Southern Alps, Italy

The Bonarelli Horizon is an important regional marker level in the Umbria-Marche Apennines. It is characterized by consisting of black bituminous shales that yield a distinctive radiolarian fauna. Black shales referable to the Bonarelli Horizon are also present in the Southern Alps. The horizon is of uniform lithology and contains radiolarian assemblages of late Cenomanian-early Turonian age throughout both the Umbria-Marche Apennines and Southern Alps. Several new radiolarian taxa have been recognised and described from the Bonarelli Horizon of both areas. Two new species are defined in this paper, namelySethocapsa bossoensisandXitus picenus.